The overall goal of this project is to provide Dr. Osheiza Abdulmalik with strongly mentored scientific and intellectual training essential to his transition to an independent researcher in the field of molecular hematology. This training will be expertly guided by his primary mentor, Dr. J. Eric Russell, co-mentor Dr. Katherine High, and a highly-experienced Advisory Committee of accomplished investigators committed to training young investigators. Training will be facilitated by the active research environment and abundant support mechanisms available at the Children's Hospital of Philadelphia and the University of Pennsylvania. The proposed work is a direct extension of the applicant's recent project and focuses on gene variants responsible for hemoglobin disorders, which are among the most prevalent hereditary disorders worldwide. The long-term goal is to unravel the mechanism(s) responsible for the baseline stability of human beta-globin mRNA, and discover ways to manipulate transgenes to encode mRNAs with enhanced stabilities. These highly stable mRNAs would be expected to accumulate to high levels and translate substantial amounts of therapeutic protein for blood disorders, with emphasis on sickle cell disease and beta-thalassemia. Three specific aims are designed to confirm and extend a substantial body of relevant preliminary data, as well as provide Dr. Abdulmalik a framework for developing skills critical to his eventual success as an independent investigator. His pilot data suggest that the stability of beta-globin mRNA can be enhanced in cultured cells by duplication of a stem-loop structure within its 3' untranslated region (3'UTR). The P.I. will extend this research by: 1) investigating and assessing the stabilities of variant human beta-globin mRNAs in vivo in stably-transfected cultured erythroid cells; 2) establishing the autonomous functions of mRNA-stability enhancing beta-globin 3'UTRs in erythroid and non-erythroid cells, because autonomously functioning mRNA-stabilizing elements would hold tremendous additional value for other therapeutic transgenes; and 3) investigating key structural features of double-stem loop beta-globin 3'UTRs that may suggest a mechanism for its mRNA-stabilizing activity. The proposed research work, combined with the didactic training and structured mentoring will provide new insights into ways to manipulate mRNA stability to develop new therapies for hemoglobin disorders and will enable the P.I. to establish himself as a successful and productive independently funded researcher.